The inner surface of a pneumatic tire may include an elastomeric composition designed to prevent or retard the permeation of air from the tire's inner air chamber. This elastomeric composition is often referred to as an innerliner. Rubbers, such as butyl and halobutyl rubber, which are relatively impermeable to air, are often used as the primary rubber component in innerliners.
The innerliner may comprise a relatively thin sheet of elastomer that is formulated with compounding additives and a curing system. The elastomer formulation may be laminated to the inner surface of a tire carcass layer of an uncured tire as the tire is formed on a tire building drum. Final cure of the composite structure produces a tire having a cured innerliner adhered to the carcass.
Properties that are desirable for innerliners include good resistance to air permeation, flex resistance, and adhesion to the tire carcass.